Conventionally, there has been an electrophotographic image forming apparatus that includes a developing device including a developing roller and a blade assembly for regulating a thickness of a developer layer held on the developing roller. Further, there has been known a blade assembly that includes a blade that contacts the developing roller and a supporting member that holds the blade in an overlapping manner.
The blade has a pair of openings and the supporting member includes a pair of positioning protrusions. The openings are engaged with the positioning protrusions, respectively, thereby determining a position of the blade with respect to the supporting member in the blade assembly. The blade is welded to the supporting member at a portion of the blade between the positioning protrusions along the blade in an extended dimension of the blade.